Preparation Of Novel Porphyrin-Pillararene Compounds And Research On Photoelectric Sensing Properties

Porphyrins are extensively investigated for electrochemically active materials and photocatalysis due to the unique conjugatedπelectronic structures,ease in modification and tailoring of the molecular structures,and the excellent solvability.However,the porphyrins have been widely recognized as active center for sensing,the lack of selective recognition ability still obstacles their applications in highly sensitive chemical sensors.In this thesis,the fourth generation supramolecular pillararene is selected as the recognition group of a specific molecule,which is connected with porphyrin through covalent bond to form a novel chemical sensing molecular material having not only photoelectric activity but also selective recognition function.The unique size effect and host guest recognition of pillararene groups are used to distinguish different kinds of guest molecules,which provids a new way for the development of novel enzyme-free sensing materials.The specific research contents are as follows:1.Research on the photo-electric dual-mode sensor for hydroquinone isomers based on the pillararene modified porphyrin derivative.A novel porphyrin derivative H₂[trans-（P5A）₂PP]modified by pillararene group was designed,synthesized and characterized by UV-Vis absorption spectrum,¹H NMR,MS,IR and DPV.A simple quasi-Langmuir-Sh?fer（QLS）method was used to deposit the target compound on the ITO conductive glass to prepare multilayer film electrodes.After characterization of the QLS film-electrodes,it was determined that the films were arranged in the form of J-aggregation on the surface of ITO conductive glass.H₂[trans-（P5A）₂PP]has different response ranges for three hydroquinone isomers.The lowest detectable concentration of hydroquinone（HQ）and catechol（CT）is 1?M.Furthermore,the cyclic voltammograms（CV）and differential pulse voltammograms（DPV）for three hydroquinone isomers at the film-electrodes of H₂[trans-（P5A）₂PP]show that HQ and CT could be distinguished by redox potential,while the resorcinol had no redox peak.This work shows that the H₂[trans-（P5A）₂PP]modified by pillararene can effectively distinguish three hydroquinone isomers via size recognition effect.This is the first photo-electric dual-mode sensor for detection of hydroquinone isomers.The present work not only expands the application scope of porphyrin derivatives,but also provides a strategy for the development of chemical sensors.2.Research on the host-guest recognition properties of porphyrins modified by pillararene and imidazole groupsThe porphyrin molecules modified by pillararene H₂[trans-（P5A）₂PP]is used as a host,and the counterpart modified by imidazole group H₂[trans-（O（CH₂）₆Im）₂PP]is used as the guest.Depending on the host-guest recognition,the fluorescence of H₂[trans-（P5A）₂PP]and H₂[trans-（O（CH₂）₆Im）₂PP]was quenched at low concentration.The interference of quenching caused byπ-πinteraction between porphyrins was eliminated through the self-titration experiment of the H₂[trans-（P5A）₂PP].The host-guest composite system of the H₂[trans-（P5A）₂PP]@H₂[trans-（O（CH₂）₆Im）₂PP]was further confirmed by IR,¹H NMR and DLS.The dissociation of the H₂[trans-（P5A）₂PP]@H₂[trans-（O（CH₂）₆Im）₂PP]complex and the appearance of a new H₂[trans-（P5A）₂PP]@ADN complex are discovered by ¹H NMR after the addition of the new guest molecule adiponitrile（ADN）.The results show that the reversible conversion of the host-guest complexes system.This work provides an excellent way for the recognition of specific guest by pillararene modified porphyrin derivatives.